JOURNAL OF QUATERNARY SCIENCE (2020) 1–13 ISSN 0267-8179. DOI: 10.1002/jqs.3192 Comparisons between marine productivity and terrestrial input records in the Gulf of California over the last 28 ka ELSA ARELLANO‐TORRES, 1 * ASTRID J. MORA‐RIVERA, 2 PAOLA VÁZQUEZ‐ROMERO, 2 ENRIQUE H. NAVA‐SÁNCHEZ, 3 JUAN JOSÉ KASPER‐ZUBILLAGA 4 and M. SOCORRO LOZANO‐GARCÍA 5 1 Facultad de Ciencias, Departamento de Ecología y Recursos Naturales, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, Mexico City, Mexico 2 Facultad de Ciencias, Licenciatura en Ciencias de la Tierra, Departamento de Física, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, Mexico City, Mexico 3 Centro Interdisciplinario de Ciencias Marinas, Departamento de Oceanología, Instituto Politécnico Nacional, Av. IPN s/n, Col. Playa Palo de Santa Rita, La Paz, Baja California Sur, Mexico 4 Instituto de Ciencias del Mar y Limnología, Unidad Académica de Procesos Oceánicos y Costeros, Universidad Nacional Autónoma de México. Circuito Exterior, Ciudad Universitaria, Mexico City, Mexico 5 Instituto de Geología, Universidad Nacional Autónoma de México, Circuito de la Investigación, Ciudad Universitaria, Mexico City, Mexico Received 18 April 2019; Revised 21 January 2020; Accepted 9 February 2020 ABSTRACT: We study the marine and terrestrial contributions in the Gulf of California (GC) to understand the relationship between continental climate and oceanographic variability over the last 28 ka. In Core AII125‐8‐JPC‐20, we examine aeolian and riverine inputs as nutrients for biological productivity. We use biogenic silica (%opal), total organic carbon (%TOC) and calcium carbonate (%CaCO 3 ) as proxies for primary productivity, and lithic fraction distributions as proxies for terrigenous transport. At the core site, biogenic and lithic components are in phase at millennial‐scale in response to regional climate conditions. During the Late Pleistocene, the GC shelf area was above sea level and the western margin showed transient episodes of increased fluvial inputs. Episodic increases in %opal and reduced %TOC suggest upwelling events but ineffective C‐export to the sediment. During stadial events (Heinrich 2, Heinrich 1, Younger Dryas), regional declines in %opal, but increases in %CaCO 3 and TOC, suggest efficient C‐export by carbonate organisms. During most of the Holocene, dust inputs are higher. Episodic increases in %TOC suggest higher C‐accumulation, although this is not controlled by siliceous or calcareous organisms. In the GC, besides upwelling and current advection, nutrient inputs driven by terrestrial climate have an impact on the biological C‐pump. Copyright © 2020 John Wiley & Sons, Ltd. KEYWORDS: biogenic opal; calcium carbonate; dust inputs; fluvial inputs; grain size. Introduction Over the last five decades, numerous studies have been developed to investigate the Gulf of California (GC) in terms of atmospheric circulation and physical and biological oceanogra- phy. The GC is recognised by its high productivity due to high nutrient availability in the euphotic zone driven by advection, thermohaline circulation, vertical mixing, and coastal upwelling (Alvarez‐Borrego & Lara‐Lara, 1991; Badán‐Dangon et al., 1985; Lavín & Marinone, 2003; Roden, 1964). Nowadays, as part of a coastal upwelling zone, the gulf acts as a net source of CO 2 to the atmosphere (Rodríguez‐Ibáñez et al., 2013). However, in terms of its relationship with the continental climate, little is known about the natural source of nutrients from terrestrial sources (Muñoz‐ Barbosa et al., 2017; Ramírez‐León et al., 2015), besides sediment supply and deposition to the basins (Kluesner et al., 2014). In the GC, terrestrial inputs to the ocean are of great importance because it is a marginal and semi‐enclosed sea, where the proximity to the deserts of Sonora, Sinaloa and Baja California ensures a continental, rather than an oceanic climate (Badán‐Dangon et al., 1985; Lavín & Marinone, 2003; Roden, 1964). Studies in the GC reveal the presence of laminated sediments and high accumulation rates that allow a variety of palaeoceanographic research from seasonal to longer scales (Barron et al., 2014; McClymont et al., 2012; Pichevin et al., 2014; Pride et al., 1999; Schrader et al., 1980). The seasonal pattern distinguishes lithogenic deposits made of clay and silt from the summer and fall wet seasons, whereas biogenic near‐monospecific to mixed laminae deposits (mostly of diatoms) occur during the dry seasons (Douglas et al., 2007; Pike & Kemp, 1997; Pride et al., 1999). At larger scales, studies based on phytoplankton assemblages, geochemistry and stable isotopes reveal changes in upwelling linked to variations in climate and hydrography (Barron et al., 2004, 2005, 2014,; Pride et al., 1999; Staines‐Urías et al., 2015; Ziveri & Thunell, 2000). Despite the abundance of lithogenic material conveyed to the gulf, our knowledge of the influence of dust or riverine inputs on ocean productivity remains incomplete. In this context, we aim to reconstruct biological and terrestrial inputs to the sediments at the suborbital scale, to decipher patterns and drivers of carbon export to the seabed that could change the GC's role as a net source of CO 2 . We first determine the distribution of lithogenic material in the sediment. Secondly, we define its connection to the con- tinental climate and delivery of terrigenous material as a source of nutrients. Lastly, we compare regional biogenic records to define natural patterns of variability and document concurrent variations over the last 28 ka. Copyright © 2020 John Wiley & Sons, Ltd. * Correspondence: E. Arellano‐Torres, as above. E‐mail: elsa_arellano@ciencias.unam.mx